Method for embellishing wood



0. BROWN 3,081,159

METHOD FOR EMBELLISHING WOOD March 12, 1963 2 Sheets-Sheet 1 Filed July18, 1955 INVENTOR.

Mamh 1963 0. BROWN 3,08 59 METHOD FOR EMBELLISHING WOOD Filed July 18,1955 2 Sheets-Sheet 2 United States Patent 3,081,159 METHOD FOREMBELLISHING WOOD Owen Brown, 5013- Exposition Blvd., Los Angeles 16,Calif. Filed July 18, 1955, Ser. No. 522,500 11 Claims. (Cl. 41-41) Thisinvention relates to wood, to wood handling and re-surfacing machinery,to certain preferred methods applicable thereto, and to typicalarticles'which are the resultant products of said machinery and saidmethods.

While certain of the methods and the apparatus may be used in theprocessing of board lumber, selected edgebonded board stock and thelike, they are particularly applicable to plywood sheets; and for thisreason, without prejudice to sundry other uses, the invention will beexplained with reference to standard laminated panels.

Furthermore, for reasons which will be clarified in due course, panelshaving rotary-cut face-plies of soft woodsespecially such as exemplifiedby Douglas fir, with its well-known random hard and soft grainfigurations--are featured in the accompanying drawings, wherein aplurality of embodiments is shown. Certain of these drawings, includinga major part of the present specification, in substance, were originallyfiled Sept. 18, 1948, under Serial No. 49,964 in a former co-pendingapplication called Wood-Embellishing Means and Methods, IncludingTypical Products Thereof, which application was subsequently abandoned;hence the present application is a continuation in part thereof.

Problems of the Prior Art The method of subjecting plywood faces to theaction of different abrading means, inclusive of both sand-blasters andwire-brushing devices, has long been practiced butuntil the past fewyears--without marked commercial success. This has been due, in part, tothe high cost of manually sand-blasting such panels, failure to employsufficiently fine-grain abradant grit at relatively low pressures, andthe difiiculty of cleanly removing the surface soft grain wood withoutinjury to the hard grain figurations.

In the case of wire-brushing, where sufiiciently stiff bristles havebeen utilized with adequate pressures to take out all or most of thesurface soft wood, and at the required brush speeds, such bristles havealso deleteriously affected the hard grain portions. That is, where theoverlapped growth layers terminate, at their former areas of contactwith the knives of the lathe-head at the plywood mill, the wirebristlesas generally employed-often produce clusters of objectionablelacerations. Moreover, because of the pitch and curl of the hard grainin some firwood face-plies, it has been extremely difficult to cleanlyremove all of the softer wood from the deeper pockets formed here andthere across certain of these veneers.

Recently, however, a machine has been developed which is said toovercome the first aforesaid difficulty, relative to the lacerations. Iam presently informed that the heavy scratch marks are avoided bystationarily mounting a considerable series of rotary brushes having afixed angular contact with the moving plywood surface. Thus, presumably,certain banks of rotating brushes are mounted for contacts obliquely ofthe panels, in one direction, while other banks, also obliquelypositioned, contact the wood surfaces in an angular manner opposite tothat of said first mentioned banks.

Machines of this type are apparently not yet capable, however, ofremoving all the surface soft wood from the aforesaid pockets ofparticular face-plies; and for at least 2,617,223, issued Nov. 11, 1952,to C.'T. MeElroy and John G. Davidson.

partially overcoming this difiiculty while, at the same time, providingimproved and relatively much less expensive brushing machines which willnot produce coarse brush marks, I herein introduce an especially compactmechanism of the type I prefer in carrying out the several objects of myinvention.

General Objectives One such object is to provide, in a single machine, aplurality of wood configuring tools, one of which is an efficient,compact, low-cost brushing unit of the class described in commonassembly with a particular kind of cutting head to be hereafter definedrelative to FIGS. 1, 2 and 3 of the drawings.

Another object is to utilize such a combination machine as one preferredmeans for producing so-called spears or spear-heads, such as describedin some detail in my previously entered application called Process forOrnamenting Various Objects, Including Means Therefor and MethodsRelating Thereto, Serial No. 630,892, which has since been abandonedunder that entitlement in favor of a former co-pending continuationthereof in part called Wood Ornamenting Means, Methods and the ProductsThereof, the latter filed March 24, 1952, as Serial No. 278,281 butlater abandoned.

Another object, in line with the last aforesaid objectives, is toutilize such a combination machine, along with other stepwiseprocedures, in the production of attractively predecorated panels, to befurther detailed.

Other objects will be revealed in the remainder of this specification,as complemented by the claims and said drawings, wherein- FIG. 1 is alargely schematic plan lay-out of unified components comprising onepreferred embodiment of the invention.

FIG. 2 is the fragmental detail of a plywood face-ply,

- featuring a combination decorative motif carried through to thefinishing stage.

' FIG. 3 is a side elevation of one of the right and left stanchions onthe machine of FIG. 1, bearing right and left oscillatory arms fromwhich are carried the duality of rotary brushing wheels there shown.

FIG. 4 is the fragmental view of a plywood article which, by a minormodification of the cutting head, could be produced in part on themachine of FIGS. 1 and 3, and FIG. 5 shows another plywood fragmentsimilar to the FIG. 4 article of variant type.

In s id former co-pending application bearing Serial No. 278,281, twogeneral types of apparatus are provided, with the aid of whichaspreviously indicateda striated plywood panel can be further treated tobring out an attractive pattern of more or less pointed surfaceconfigurations called spear-heads.

Moreover, in another erstwhile co-pending application entitledVariegated Wood Products, Including Means and Methods Relating Thereto,Serial No. 33,246-now Patent No. 2,706,355 of April 19, 1955, bearingthe amended title. Method of Producing Variegated Wood Surface andProductapparatus is disclosed whereby desirable portions of the softsurface wood may be abrasively and quite smoothly removed from afaceply, without producing lacerations in the hard grain areas; whichlatter remain substantially intact and are merely given .a high polish.

This beneficial result is achieved by brushing the Wood surface athwartthe general grain trend, as therein related.

Now it is characteristic of machines having stiff brushing wheels whichturn in the same direction as the grain trend that they will, underadequate pressure, produce the lacerations 2, as aforesaid: such as seenin the lower stationarily mounting difierent banks of brushing wheels torotate obliquely against the panel surfaces from both sides-this set-upaffording a diagonal movement somewhat comparable to the diametricallytransverse action of the brushes in said last named co-pending case-thisarrangement necessitates an expensive plurality of individual banks ofbrushing wheels, which, in many cases, would remove more of the surfacewood than theoretically essential: that is, if the object is to removeonly the soft grain surface wood, and perhaps at times, in accord withcertain methods and articles to be hereafter described, leaving aportion of such surface wood above the harder growth laminations.

According to one mode of procedure, it is possible to thermochemicallytone the face of a plywood panel, using so-called activatorssolutionsmade up from heat sensitive chemicals to be further amplifiedhereinwhich produce deeply penetrating tones in the hard grain segmentsand to thence remove the soft surface wood, only, whereby to bring out amore contrasty and more optically appealing effect than appearedoriginally. Copper sulphate and nitric and hydrochloric acid activators,for instance, are among those which may be so utilized; as see later,more specific reference thereto.

It has been found, however, that the desired effect is impaired if,during the brushing operation, any appreciable hard grain is removedalong with the soft textured wood; and even if the hard grain be onlytaken from the frontal areas 3 of the growth ring laminae, at whichplaces hydrochloric activators often produce attractive black markingsat the very edges of particular hard grain layers.

The Brushing Wheels After repeated experiments, it has been determinedthat the hypothetically preferred action is one wherein the brushesrotate both transversely and obliquely; and this result, in a singleautomatic machine, has been accomplished without having to lay up theface-plies transversely (as explained in said Patent No. 2,706,355), andwithout having to provide an expensive dual series of stationarilymounted brushing wheels for right and left oblique con tacts with thepanels.

In brief, said result is obtained by the expedient of mounting one ormore brushing wheelsor, if required, sets thereoffor oscillatorymovement.

Thus, in the more or less schematic view of FIG. I, a duality of typicalbrushing wheels 4 and 5 are provided, having respective arbors 6 which,in turn, are swivelmounted within forwardly and rearwardly disposed yokemembers 7 of the right and left sets of wiggle-bars 8, socalled; one ofwhich latter sets is shown for greater clarity in the detail of FIG. 3.For extra bracing, the bars 8 are inter-connected by the arm 9; androtation of both brushes, in this particular assembly, is provided forby the train of belting 10 and 11 leading back to motor M.

Oscillatory movement of the brushing wheels is produced by the mechanismat left, subject to obvious engineering substitutions and adjustments,wherein the wigglebars on that side are integrated with a crank 12projecting from the collar 13-si1nilarto collar 13 of FIG. 3. Crank 12is pivoted to the pitman or link 14; and pitman 14 is also pivoted, asindicated, to a downwardly extending link (not seen) having the upperboss 15.

Said downwardly extending link operates, approximately midway of itslength, from a stationary pivot (not shown in the relatively smalldrawing); and at its lower end is provided with the offset link 16 atlower boss 17. Link 16 is pivotally connected to the crank 18 extendingaccording to this version-from a speed reducer and regulator group 19.The belting 2t) and complementary pullevs, associated with motor M, areself-explanatory, and the elements referred to as not seen and not shownwill be so obvious, to skilled individuals, as to require no more thanthe above brief reference thereto.

Obviously, the turning of crank 18 on the gear box produces a forwardand backward stroke of the pitrnan;

4 and, through said pitman, to crank 12, the resultant oscillation ofthe wiggle-bars S imparting like movements to the brushing wheels 4 and5. It is apparent, of course, that instead of the specific arrangementshown a more direct hook up between the pitman and cranl: 18 could beprovided.

The panels 21, 22 and the like may be moved relative to the brushingwheels in any desired manner, as here conveniently indicated by means ofa plurality of chains 23 trained over the sprockets 24 and driven bymotor M through belting 25 and 26 and the speed reducer 27. Very lowpusher-dogs 28, for adequate clearance from wheels 4- and 5 and theblades of the cuttingheadto be explained shortlyare self explanatory.These could, by option, be replaced by a pusher bar (not shown)interconnecting all three chains; an alternative which is old and wellknown in the related art. Among the possible other options, of course,are a system of feed and suitably positioned back-up rollers, comparableto such as are shown in the hereafter referred to patent of WilhelmClefi.

The stanchions 29, FIG. 3, are each provided with upstanding posts 30over which the collars 13 are journaled; and right and left compressionsprings 31, in combination with each movable adjusting sleeve 32havinginner threads engaging threads 33 011 the upper area of post 3ilserve asautomatic means to bring any desired pressure to bear on arms 8 and,therethrough, upon brushes 4 and 5 at their points of contact with thepanel 21. As earlier intimated, each of the shafts 6 turns freely withinthe swivel-bearings 6.

Phantoms 33 and 34 represent hoods having conventional exhaust fans incombination (not shown), whereby to carry away the wood particles whichare removed by the respective working heads.

Operating Means and Modes When panel 21, for example, is fed to thecombination machine, each of the rapidly rotating brushes will describean oscillatory pattern as generally indicated by phantoms 35 and 36. Theoscillatory movements in either direction may be quite limited, however,and do sirably so, whereby to produce not only a brief sidewide scrapingaction against the direction of the grain trend but, also, in order tocause a continuous, instantaneous stiffening of the brushes within anarrow confines of each right and left oscillaiton: thus imparting amomentary, but sufficiently yieldable, gouging or digging effect at thehypothetical center of the oscillatory movement entirely across thepanel surface.

This digging effect, under the required pressures, will not impair thehard grain; but, taking place as one component of a brushing actionoccurring continuously, and almost diametrically, athwart the generalgrain trend, it enables the brushes to exert a more effectual gougingaway of certain soft wood tending to remain within pockets and the like,as was mentioned heretofore. Furthermore, such a result can be hadutilizing wire bristles of small sizes; and the latter, where the woodhas been first thermochemically pre-softened in the manner hereafterexplained, may be as small as .005 (five thousandths) of an inch: thusfurther minimizing, or largely eliminating, the effect of brush marks.

It is evident, of course (where such a full-etched result is desired),that the cleaner removal of the soft wood, even from frequent panelshaving deeply sloping and curling hard and soft grain portions, is madepossible by the combination of a nearly direct side-wise movement of thebrushes in addition to said digging effect, which is also applied moreor less sidewise of the grain trend. Such an action, and the resultingphysical effect upon the wood surface, is obviously not possible wherethe brushes are only stationarily mountedeven though obliquely so withreference to the panels.

Moreover, since the panels themselves are traveling relative to thebrushing head or heads, it is apparent that there is also continuouslytaking place an angular brushing contact which is the substantialequivalent of that which would be produced if the wheels 4 and were,indeed, stationarily mounted for oblique contacts; but with the addedadvantage, however, of the continually changing angular actioncoincidental with each back and forth oscillation. That is, at eachreversal of movement-extending entirely athwart the panelthere isexerted a two-way gouging effect, as compared to a oneway effect, evenwhere stationarily mounted brushes are obliquely disposed in oposedrelations as aforesaid.

Because of the greater efficiency of brushing wheels 4 and 5, as softwood removers, a much smaller number of brushesof a given bristle sizeand stiifness--can be used on a particular machine; but needless to say,the tandem thereof in FIG. 1 is only suggestive, and any desirableplurality of such brushing heads may be provided, and whether or not indifferent assemblies or driven from separate power units.

It is also provided that any preferred number of stationarily mountedbrushing wheels 37 may, by option, be included in a given machine. Suchbrushes rotate in the same direction as the general grain trend, andcould be only sulficiently stilf to aid in removal of the soft woodwithout producing lacerated areas 2, as in FIG. 2.

Moreover, in order to elfect a still cleaner removal of the soft woodwhere such a result is desired, either or any of the brushing wheels maybe operated contrary to the direction of rotation of another or othersof the as- .sembly. Thus, with reference to both FIGS. 1 and 3, forexample, by merely criss-crossing the belt the brushing wheel 4 can beoperated according to arrow 38, while wheel 5 turns according to arrow39or vice versa according to arrows 40 and 41.

Other Procedures It is by now clear that when panels 21, 22 and the likepass entirely through the brushing head or heads they may, ifadditionally required, enter automatically under the feed-roller 42,having a suitable back-up roller-not shown-therebelow; thence passingunder the cutting head 43 of planer type mechanism, which is providedwith a requisite plurality of specially serrated knives 44. Theseknives, it will be seen, have areas 45 thereof formed to produce aconsiderable multiplicity of selectively narrow striations which, uponsubsequent thermochemic processing to be explained, serve to define theinnumerable small spears having spear-heads 46 of FIG. 2; some of whichspears may be relatively narrower and wider than others of the same.

The areas containing spears 46, then, will be imposed according to onepreferred pattern exemplified by the 'panel 1 of FIG. 2-in the form ofbands 47; these bands, collectively, defining other spaced and widerbanded areas 48 of the previously configured wood. This objective isaccomplished by forming knives 44 with sufficiently deep gaps or skips49, which are in exact registry with one another as are the areas 45.

Obviously, where the skips occur the closely spaced striations will notbe imposed. And in order to produce the striations cleanly through theridges of hard grain, as an operation subsequent to the removal of thesoft surface wood, it is desirable to feed the panels to the combinationmachine with the grain trend as is customarily done in comparable otherwood-working procedures; it being assumed that the knives 44 will berotated contrary to the movement of the panels. Brushing element 37' isfor smoothing the planer cuts. By option, one or more thereof could bemounted for this purpose; such as elements 4 and 5 and/ or 37, forexample.

Incidentally, it will be readily apparent to skilled individuals thatthe conveyor chains could end at a point short of feed roller 42, wherethey would normally turn downwardly over other sprockets 24 (not shown);and the panels 21 and the like would thence be further moved solely byroller 42 along with any required auxiliary drive roller mounted on thedelivery side of the work head 44.

The reason for mounting the cutting tool as shownfor later contact withthe panels-is in order to fully overcome the possible difficulty ofobtaining a clean removal of the soft wood, after imposition of thestriations. Should it be found, in practice, that a fully satisfactoryabstraction of the soft grain can be effected after the panels have beenstriated (a result which, parenthetically, I have accomplished since theoriginal file date of the first entered application hereof, bearingSerial No. 49,964), I have no objection to reversing the relativepositions of the kerfing and brushing components.

Right and left elements 21*, 22 are schematic guide means, and may beany preferred type thereof.

Although panels 1 may be additionally processed, in obvious other ways,I prefer thermochemic treatments whereby to accent the spear-heads whileautomatically imparting an attractive complementary toning to theintermediary zones or hands 48 substantially as shown.

Accenting the Spear-Heads Thus, for the effect seen in FIG. 2, theselected activator is a sufiiciently strong aqueous solution of coppersulphate; and while the activator may be made either somewhat strongeror weaker without materially modifying its thermochemic sensitivity andwood-toning character, my own solutions of this order are produced bydissolving 3 ounces of copper sulphate crystals, of the ordinarycommercial grade, in each quart measure of tap water-the latter heatedto speed up the dissolving action. The selected surface of the panel isimpregnated with the solution, dried, and subjected to the action of aheating unit of the general class thereof disclosed in the aforesaidPatent No. 2,113,679 to Wilhelm Clefi and in No. 2,431,148 to F. R.Stover. Or see the comparable device shown in said former copendingapplication bearing Serial No. 278,281. Such panels may be marketedunsealed or given a coating of any suitable clear protective material,such as nitrocellulose lacquer sanding sealer for example. The same,however, would not be normally sanded.

Before sealing, if desired, the panel 1 may receive a wash coat orimpregnation of any satisfactory chromatic toner, exemplified by asaturated solution of picric acid or a selected aniline dye. Whereinsuch positive colorizers are relatively impervious to heat and havelittle or no chemical afiinity for the selected activator, they may, byoption, be applied before the heat treatment. A more preferredembellishment, however, will be detailed hereinafter with especialregard to FIGS. 4 and 5.

Ordinarily, copper sulphate solutions, in the thermochemic process, willinitially produce jet black tones in the soft grain to the virtualexclusion of the hard grain areas. But if localized heat of a sufiicientintensity is applied, the hard wood will also begin blackening at theedges of each hard grain area. It is this characteristic reaction of thecopper sulphate activator which makes possible the attractive black tipsat the spear-heads, as well as along the edges of the grain layers 48and the sides of the spears, without darkening the pattern as a whole;that is, if the heat treatment is not unduly prolonged.

Another of possible formulas for darkening the spearheads and areas 48'involves the substitution of a compound solution of copper sulphate andhydrochloric acid, such as disclosed in my former copending but laterabandoned application, Wood-Enchancing Method and Article, filed Jan.20, 1955, as Serial No. 483,052. Such a formula, however, is bestadapted to panels which have been grooved before thermochemic treatment;as see the later description herein relative to said FIGS. 4 and 5.

enemas Further Modifications As mentioned heretofore, it is sometimespreferable to additionally treat the panels 1 before applying a sealcoat thereto; it being understood that such a coat could be omitted bythe original processor and applied by the subsequent purchaser. In fact,some purchasers may, in order to obtain particular decorative effects,prefer to leave the panels unsealed and Without further processing.Attractive rustic or tropical effects, for example, may be had bymodifying the chemical formula which was described with regard to saidFIG. 2. article and omitting any sealer coat.

Thus, referring now to FIGS. 1 and 4, it is apparent that by asubstitution of differently formed planer blades, so as to eliminate thedeeper segments 49, the resultant panei 1 would-before furthertreatmentbeeome the striated equivalent of standard closely groovedpanels commonly called combed plywood, and heretofore produced underPatent No. 2,286,068 to Donald Deskey. It may, therefore, beconveniently assumed that the panel 91 of FIG. 4 is either amodification of the aforesaid panel 1, omitting the broader bands 48, orthe fragmental corner from a plywood sheet produced in accord with theDeskey patent, but further processed according to procedures which willnow be described.

Panels of this general order are so closely grooved that theirrespective original grain patterns, in the natural, are substantiallyobliterated; the hard and soft grain portions being so nearly alike innatural tone that one thereof is but faintly distinguishable from theother. This applicant is believed to have been the first to discoverthat, when also etched and thermochemically toned in special ways, suchgrooved or combed panels could be largely transformedas to their generaloptical effectand their scarcely visible grain patterns brought out andenhanced by thermochemic treatments comparable in some respects to thephotographic process.

Moreover, since the individual grooves and complementary ridge portionsare quite narrow and closely spaced, when the outermost soft texturedwood has been etched away, instead of the thus raised hard grainpresenting an appearance such as seen at 3 in the broad bands 48 of FIG.2, the multiplicity of spear-like spines 46 and the like will beproduced as heretofore mentioned. But where such a panel, after anetching (brushing) operation, is then thermochernically treated,including the heretofore described application of copper sulphatesolution, the remaining surface soft wood is not materially darkened;hence the contrasty effect seen in FIG. 2 where only the so-calledspear-heads 46 have been intensely blackened.

It has been further discovered, in the interim, that a desirably lesscontrasty and more rustic or naturalistic effect may be produced, onsuch panel stock, whereby the blackened spear-heads may be retained and,in addition, the remainder of the face-ply toned to a mellow brownishshade admired by architects and interior decorators alike. And panels soprocessed may be used after a combination of thermochemic and etching"treatments, for rustic or tropical motifs, or may be somewhat furtherdarkened and protectively covered by merely applying but a singlecoating of nitrocellulose lacquer or standard other clear sealermaterial thereto.

Concerning Activators To produce the effect generally indicated in FEG.4, the surface of panel 91 is first impregnated with a thermochemicsensitizer--or so -called activatorcontaining both copper sulphate andhydrochloric acid in a watery solution. As disclosed copendingly, theexact relative proportions of the chemicals and the water component maybe varied considerably without greatly altering the tonal effectobtainable therewith. However, after much experimentation, I prefer acompound solution produced by dissolving 3 ounces of copper sulphatecrystals, avoir- 8 dupois, in each required quart measure of water (asalready explained for making the straight copper sulphate activator),and by producing an acid solution comprising one part by volume ofhydrochloric acid, technical, to each five parts of tap water. Then toeach one part of the hydrochloric acid solution is added two parts byvolume of the copper sulphate solution and the composite liquid wellstirred for intermixing.

it is a natural characteristic of these two chemicals that, when thuscombined, applied to the panel surface, and the latter subsequentlyheated, the normal thermochemic action of neither of them is lessened bythe other; but each thereof cooperates with the other to produce a tonaleffect of which neither of them, used apart from the other, would becapable. The copper sulphate, reacting therrnochemieally, not onlyblackens the surface soft grain wood but, in coaction with thehydrochloric acid, more rapidly blackens not only the ends of thespearlike spines (to be later delineated by brushing) but all sectionsthereof which are at surface level: this result being obviouslysuperinduced by the additive action of the acid. Moreover, instead ofhaving to carefully control the amount of heat to stop the blackening,as in the treatment previously explained relative to FIG. 2, theselected face-ply may be rapidly blackened throughout. This eliminatesany need for carefully exactly controlling the amount of the heatapplied to the panel surfaces. Heating apparatus of the general classdisclosed in said Cleft and Stover patents may be used; and, afterheating and blackening, each panel 91 is then ready for brushing. insmall production, an ordinary gasoline blow torch may be substituted andmanipulated manually.

The brushing stepwhich is preferred to sand-blastingcan be carried outin a machine such as seen in FIG. 1 but minus the head 44; or,alternatively, a single stationarily mounted rotary brush, similar tobrushes 4 and 5, may be used. Lacking the oscillatory motion of thebrushes 4 and 5, such a workhead will produce minute brushmarks--assuming that the panels will be moved endwise as seen in FIG. 1.But owing to the fact that the thermochemic action of the activatorgreatly softens the outermost soft textured woodin fact, to the fulldepth at which the chemicals penetratedit is possible to use a brushingwheel having bristles so small and so pliant that such brush marks arescarcely noticeable. My own comparable brushing wheel has bristles of.005 inch; and this is a preferred size for use in the describedprocess. Obviously if the oscillating brushes 4 and 5 are used, underlight pressure contacts, a'ccmparable result will be had but withoutperceptible brush marks, longitudinally of the panel or otherwise; andit is clear that for use with such previously pre-softened panels, onlyone of the brushes 4- or 5 would usually be ample.

Following both therinochemic and brushing treatments, the previouslystriated panel 91 will now have the prominent, irregularly formed spines92 and each of these terminating in the blackly accented, more or lesswell defined spear-heads 93. However, while the combined chemicalsdarkened the remaining soft wood which now lies at the new surface level(to the aforesaid mellow brownish shade), all of the blackened,previously outermost soft grain wood was removed. Thus, instead of allsections of the spines 92 being blackened, those areas of any thereofwhich previously lay underneath the removed soft grain, as at segments94, were but partially effected by the heat treatment and merely tonedto dark amber shades for the most part.

Moreover, according to the method which is preferred for producing thepanel 91, a considerable portion of the soft grain surface wood remains:not only within the deeper parts of the grooveshere only indicatedgenerally by the parallel recesses 95but frequently overlayingsubstantial, still unexposed sections of the hardgrain spines 92: as atsegments 96.

Production Procedures Such panels, in this state, can readily beproduced in volume with the use of power operated equipment for each ofthe respective grooving, impregnating, heating and brushing operations;and while I do not, in the present application, show mechanical meansfor applying the activator to the selected face-plies, the equipment fordoing so may be inexpensively constructed in accord with well knowndevices of the prior art. See, for example, the coating device shown inPatent No. 1,026,921 to W. W. Nuss, in which a cylindrical fiber brushrevolves partly submerged in a holder for liquid; which latter is pickedup by the continuously wetted brushing wheel and applied to theunderside of the work as it travels thereover. The particular value ofthis type of applicator resides in the fact that the liquid would notonly be rubbed onto the surface of the panels 91 but worked well downinto the grooves 95. Obvious other means may be utilized. Thus if itshould be desired to apply the liquid from above, roller-coaters of wellknown construction may be used in train with a rotating fiber brush (notshown), the latter serving to work the liquid sensitizing materialdownwardly into the grooved portions. Of course the liquid may beapplied manually, utilizing Tampico bristle brushes of the class calledscrubbing brushes.

It isalso apparent that in volume production, the ,originallyun-striated.panels could travel continuously through grooving'apparatus such as thework head 44 of FIG. 1; thence-toan applicator such as describedrelative to said Patent No. 1,026,921, or one which applies the liquidfrom above; thence to a drying and heating unit exemplified by theaforesaid patents to Cleff and Stover; .and, finally, under a brushinghead having one or two brushes 4 and/or 5 of FIG. 1, or only a singletransversely ,disposed brushing head mounted for straight-over rota-;tion co-longitudinally of thegrain trend, as previously explained andindicated generally in said Cleif and Stover .patents. The cost of therequired chemicals would be negligible: 'thepresently estimated figurebeing less than /z cent for each fully impregnated 4 by 8 foot panelboard. I

Still a further-and highly importantadvantage of [panels 91, in thestate described, is the fact that they may .be additionally processed totone them to almost any desired basic color, whereby to harmonize withwidely variant interior decorative schemes. Thus they may beinexpensively further toned to approximately match or ,to complement thecolor of rugs and drapes; and where .used in single wall treatments, theremaining wall spaces may be of plaster tones according to the knowncolor of ,the panels or vice versa.

Moreover, the toning of the panels may either be .done' bythe processoror by the purchaser. Where used .in large quantities in tract houses,for example, the ,buyerusually a corporati0nwould turn the panels 91over to the painter or wood-finisher; and each panel in turn, havingbeen laid fiat on a suitable table, with the grooved side up, may thenbe rapidly manually further treated as follows:

First a filler mix or slurry is made from ordinary water-dispersible drycolors. If it is desired to produce a basically White-toned panel with apredominantly black accent, the slurry may be made by intermixingso-called titanium white, of the kind chemically identified as rutiletitanium calcium dioxide in a ratio, say, of 30 to 70 (that is, 30 percent of the aforesaid substance intermixed with 70 percent of calciumsulphate used as an extender). One well known product such as describedis produced by the Titanium Pigment Corporation and marketed under thebrand name of Titanox No. RCHT-X; the desired amount of ordinary tapwater being added to form a slurry of medium creamy consistency. Insmall production it is best to use a widely open container for thisintermixed with the Water.

In small production, a convenient way to apply such a slurry, orso-called filler, is to dip it out of the container with a cup and pourit across the middle of the panel transversely. This operation is thencequickly followed by means to spread the slurry evenly over the remainderof the panel, forwardly and backwardly, an ordinary hand brush filledwith Tampico fiber bristles being sufficient to both spread the slurryand to simultaneously rub it well into the grooves 95. Immediatelythereafter, the surface of the panel may be rapidly wiped down with anitro-cellulose sponge which was previously wetted and wrung out but letin a moist, softened condition. However, a more preferred Wiping stepwill be explained shortly.

This operation will not only smooth up the pigmentation produced withthe aid of the Tampico brush but will, in large measure, remove thatportion of the filler or slurry which previously covered the high areas;mainly where the exposed hard grain is present. All of the soft grainareas will take up a sufficient amount of the slurry to become opaquelycoated and impregnated, and the slight remaining film of pigment overthe hard grain spear-heads 93 and the like can thence be quickly largelyremoved by a rapid wipe-off, using a No. 2 moistened sponge which hasnot become loaded with pigment. .For the effect of a cleaner wipe-off,however, it is preferable to quickly and finally rub the whole panelsurface lightly with small pads of paper, such as the calendered pagesfrom old telephone directories, which are conveniently halved at thecenter and each half page folded twice to form a wiping element of handysize. The resultant panel has an attractive tapestried elfect, beingrichly accented but not over-accented.

An alternativeand preferred-method of clearing the ,hard grain,following the rubbing in operation with the Tampico bristle brush, is toagain rub the surface with a wiping device having a flexible rubbersqueegee blade:

.such as are commonly employed as window wipers. In

the latter case, the final wipe oif with paper is not essential, but allof the ridge portions defined by the striae should be on substantiallythe same surface plane.

In short, if any of the ridges are deeply recessed, they would not becontacted by the squeegee blade.

(It will, of course, be understood that these procedures relate only tosuch small production jobs as may, for

"example, be performed by the average painter or homecrafter.)

A Preferred Method Applicant prefers this Wipe-off operation, utilizinga yieldable squeegee or doctor blade, so-called, to the sponge methodfor the reason that sundry of the described spearheads tend to becomesnagged against the No. 1 or No. 2

'spongesand even worse where conventional wiping rags are attempted.Moreover, since the spears often are pointed in two directions, thedifficulty cannot be overcome by merely wiping with the grain trend. Theproblem is one which is peculiar to the particularl products hereindisclosed, having said pointed spear-heads, and much experimentation wasconducted before the most approved method was discovered: that is, byutilizing'a to one which can be speedily performed with motorizedequipment. See, for example, FIGS. 7 and 9 in my prior co-pending butsince abandoned application called Multidecorated Wood Product, ItsMethod of Manufacture, and Means Therefor, filed Sept. 18, 1948, asSerial No. 49,963.

Panels so treated can be stacked or leaned against one another untildry, when they will be ready to receive a protective seal coat asreferred to heretofore. Such a coating may be brushed on, or,preferably, applied on the job with a portable spray gun. Needless tosay, these operations may all be performed in the plant of the originalprocessor with the use of existing or readily constructed types ofpower-driven equipment. But since such equipment is not per se claimedherein, and the manual method will sufiice to readily carry out theessential steps, the same are not graphically shown or described.

Those skilled in the mixing of pigment colors will require no furtherinstruction wherein the basic tone of the panel 91 is to be someselected color instead of white. One or two desirable formulas will,however, be given for the benefit of those who may wish to try outcertain color shades experimentally before adopting the one or ones mostsuitable for particular effects. Thus one kind of gray mix may beproduced, in small quantity, by utilizing with each four ouncesavoirdupois of titanium white a level A teaspoonful of drop black in drypowder form. For this purpose the small plastic or metal spoons sold tohousewives for culinary purposes will be satisfactory. The pigments aremixed to a medium creamy consistency with tap water, as describedhereabove, and applied to the panel in the same manner with like wipingoperations.

If a warm dark beige basic tone is desired, the slurry may be made inthe proportions of titanium white 4 ounces, ferrite two level teaspoonsfull, metallic brown iron oxide two level teaspoons full, and drop blackdry powder level teaspoonful. Water is added as required. Applicant inhis own slurry mixes used C. K. Williams & Co.s metallic brown oxide No.B-2390 and their grade of ferrite (ferric iron oxide) having the stocknumber Y05087. This supplier has plants at Easton, Pa., East St. Louis,111., and Emeryville, Calif, and sales offices in principal cities. Themain headquarters office of the Titanium Pigment Corporation is at 111Broadway, New York City, N.Y.

Varying the Basic Formula The number of possible thermochemic proceduresis by no means limited to the ones described, relative to the panel 1 ofFIG. 2 or the panel 91 of FIG. 4. Thus, as one of sundry possible othertreatments, the effect seen in PEG. 5 may be obtained by still anothermodification in the thermochemic activator. In this view, the previously grooved face-ply of panel 97 has been impregnated with a compoundsolution comprising desirable proportions of copper sulphate and nitricacid, and usual technical or commercial grade being satisfactory. Aswith respect to the compound solution of copper sulphate andhydrochloric acid, the proportions of each may vary greatly withoutcritically altering the general result to be attained. It is, however,necessary that a suflicient amount of the copper sulphate be added tothe water component to obtain blackish tones in the surface wood in thepresence of locally applied heat, since, in this formula especially,such a reaction is necessary in order to both tone the face-ply and tothermochemically soften the soft textured portions of the wood surfaceas a pre-requisite to the subsequent brushing operation-according to theprocedure given relative to panel 91. The particular reason for this, inrelation to panel 97, is that nitric acid, in the proportions used, haslittle or no wood-softening action, and only a wood-toning action uponapplication of suitable heat. However, such a compound solution must,also, contain a sufficient amount of the nitric acid Li to producedistinctly reddish thermochcmic tones in the wood, which it will dowithout reference to the copper sulphate in solution with it.

After many experiments, this applicant arrived at preferred proportionsof the respective ingredients comparable to those employed with respectto the panel 91. In brief, a preliminary solution is made by adding fiveparts of tap water to each part of the nitric acid; and to one part ofthe resultant liquid is thence added two parts of the first mentionedcopper sulphate solution, produced by dissolving about three ounces ofthe dry crystals in each quart of tap Water. The composite solution, oractivator, is thence applied to the panel surface and the latter driedand heated in the manner heretofore detailed.

The more heat-sensitive nitric acid will, initially, quickly react inand with the surface woodboth hard grain and softto produce reddishtones shading toward burnt orange. This reaction is quickly followed,however, by an independent reaction of the copper sulphate component;the latter changing the previously reddened soft grain surface wood toblack and, if the heating action be sufficiently intense or sufficientlyprolonged, it will also produce blackish tones at the tips of thespear-heads 98. Ordinarily, it is not preferred-for the effect seen inFIG. 5-to carry the heating step beyond the stage at which the surfacesoft grain wood is fully blackened; after which the panel 97 ispreferably fed to a mechanically operative brushing element in themanner explained relative to panel 91.

The brushing operation will remove substantially all of the blackenedsurface wood, bringing out and leaving the spear-heads 98 of thepreviously exposed hard grain relatively darker in tone than thosesegments thereof which were below the original surface prior to thebrushing action and, hence, less affected by the heat. Such protectedbut now also exposed areas will be lighter in tone, shading graduallydarker toward the spear-heads substantially as shown. Thus the greatestcontrast occurs where each spear-head overlaps the lamina immediatelyadjacent the same, whether the adjacent wood be the hard grain of thenext adjoining spear or a segment of the re-exposed soft grain Wood.

The panel 97 may be marketed in this state, or may be sealed with asingle coat of clear nitrocellulose lacquer of any selected well knowntype; or any elected other clear sealer material may be used. Panels sotreated are especially suitable for warm reddish brown color schemes,and go especially well with real maghogany or so-called Phillipinemahogany trim: also as paneling on fireplace walls to harmonize with redbrick fireplaces. Obviously, too, they may be further processed in anydesired manner, such as by the pigmentation and wiping treatmentsexplained relative to the FIG. 4 panel.

Although certain preferred expressions of the invention have beendisclosed, these are primarily illustrative of the possibilities. Theinvention, therefore, is not to be limited thereby, but rather by thelanguage of the properly allowable claims hereto.

I new claim:

1. The method of removing relatively softer textured surface wood fromthe contiguous harder grain portions thereof on the selected face-ply ofa plywood panel, which comprises positively abra sively brushing saidfaceply in respective rotative and oscillatory manners simultaneouslywhile said panel, itself, is in continuous movement, which procedureincludes: imparting said movement to said panel and applying a laterallycontinuous to-and-fro sidewise motion to the primary driving means ofthe brushing means.

2. The method of toning and of mechanically configuring a wood surfacewhich includes impregnating said surface with a compound aqueoussolution containing a known quantity of nitric acid as well as a knownquantity of copper sulphate; heating said surface until 13 both blackishand reddish tones are thermochemically developed in the respectivesofter and harder textured surface wood; and abrasively removing acomponent of the outermost softer grain portions thereof.

3. The method of toning and blackening a wood surface thermochemicallywhich includes: impregnating said surface with an aqueous solutioncontaining a known quantity of liquified copper sulphate of a knownstrength and wood-sensitizing property in the presence of adequate heat;drying said surface; and heating it until the desired amount ofthenmochemic blackening has taken place therein.

4. The method of removing relatively softer textured surface wood fromthe contiguous harder grain portions thereof on the selected side of awood-surfaced object, which includes positively abrasively brushing saidselected side thereof in respective rotative and straight-lineoscillatory manners variable to-and approximately right-angular to-thelongitudinal axis of said object while the latter is in a substantiallycontinuous one-way movement; which procedure includes imparting therequired movement thereof to said object.

5. The method of toning and darkening a wood surface thermochemicallywhile softening an outermost component of the softer-textured surfacewood, which includes: impregnating said surface with an aqueous solutionconsisting solely and normally of a plurality of known thermochemicwood-sensitizing and wood-toning active components thereof, one of whichcomponents is copper sulphate; impregnating said surface with saidsolution; drying said surface; and heating the same until the desiredamount of thermochemic toning has taken place.

6. The method of removing relatively softer textured surface wood fromthe contiguous harder grain portions thereof on the selected side of awood-surfaced object; namely: by positively abrasively brushing saidselected side in respective rotative and oscillatory mannersimultaneouslysaid rotative and oscillatory actions comprisingconcurrent plural (respective) movements of the same brushingmeans-while said object itself is in continuous motion which procedureincludes imparting constantly repetitious motions of oscillation to theprimary driving means of the brushing means and the required movementthereof to said object.

7. The method of removing relatively softer textured surface fibers fromthe contiguous harder textured grain portions of a wood-surfaced object,which comprises: imparting a continuous one-way movement to said objectand positively abrasively brushing a selected side thereof bothrotatively and regularly repeatedly in a laterally continuous to-and-fromanner crosswise of the normal grain trend, as well as regularlyrepeatedly forwardly and backwardly of a common axial center of therotational movement.

8. The method of removing relatively softer textured surface Wood fromthe contiguous harder grain portions thereof on the selected side of awood-surfaced object which includes: non-reliably brushing said siderota- 14 tively while moving said object along a path of travel contraryto the directional motion of rotation, and the concurrent furtherbrushing of said surface positively ab-rasively in a transverseto-and-fro axially swingable manner.

9. The method of toning a wood surface thermochemically which includes:impregnating said surface with a compound aqueous solution, comprisingknown respective amounts of liquified copper sulphate and nitric acid,of a known composite strength and wood- :sensitizing property in thepresence of the required intensity of heat; drying the surface; andheating it until the desired amount of thermochernic toning has takenplace therein.

10. The method of brushing away the outermost soft textured fibers froma wood-surfaced object having relatively harder and softer grainfigurations, with a desirable minimum of visible brush marks, whichcomprises: continuously moving said object in a one-way path of travelwhile concurrently brushing said surface positively abrasively, and bothrotatively and regularly repeatedly athwart the normal grain trendthereof; which latter procedure includes brushing said object in atransverse to-and-fro swingable manner.

11. The method of toning and blackening a wood surface thermochemicallywhich includes: impregnating said surface with a compound aqueoussolution, comprising known respective amounts of hydrochloric acid andliquified copper sulphate of a known combined strength andwood-sensitizing property in the presence of adequate heat; drying thesurface; and heating it until the desired amount of thermochemictoningincluding said biackeninghas taken place therein.

References Cited in the file of this patent UNITED STATES PATENTS749,004 Wadamo-ri Jan. 5, 1904 764,872 Stewart July 12, 1904 1,431,917Antaramian Oct. 17, 1922 1,566,985 Shuler Dec. 22, 1925 1,794,194Meyercord et al. Feb. 24, 1931 1,802,069 Schmid Apr. 21, 1931 2,024,257Snelling Dec. 17, 1935 2,431,148 Stover Nov. 18, 1947 2,467,194 DeWittApr. 12, 1949 2,617,223 McElroy et al. Nov. 11, 1952 2,634,534 BrownApr. 14, 1953 2,635,653 Hennell Apr. 21, 1953 2,706,355 Brown Apr. 19,1955 FOREIGN PATENTS 652,508 Great Britain Apr. 25, 1951 OTHERREFERENCES chapter 13, pages 269-298; at page 281 in particular.

1. THE METHOD OF REMOVING RELATIVELY SOFTER TEXTURED SURFACE WOOD FROMTHE CONTIGUOUS HARDER GRAIN PORTIONS THEREOF ON THE SELECTED FACE-PLY OFA PLYWOOD PANEL, WHICH COMPRISES POSITIVELY ABRASIVELY BRUSHING SAIDFACEPLY IN RESPECTIVE ROTATIVE AND OSCILLATORY MANNERS SIMULTANEOUSLYWHILE SAID PANEL, ITSELF, IS IN CONTINUOUS MOVEMENT, WHICH PROCEDUREINCLUDES: IMPARTING SAID MOVEMENT TO SAID PANEL AND APPLYING A LATERALLYCONTINUOUS TO-AND-FRO SIDEWISE MOTION TO THE PRIMARY DRIVING MEANS OFTHE BRUSHING MEANS.